The invention refers to an apparatus for obtaining nutritive substances by extracting bones and meat which optionally adheres thereon, comprising a receptacle for accommodating the bones and the liquid used for extracting, preferably water, in which receptacle at least one rotating stirring member is provided, the receptacle being tiltable about a horizontal axis so that its content gets to a coarse sieve for separating the bones and the coarse elements from the liquid and the fine elements.
As is well-known, bones which are obtained by manually dividing slaughtered animals contain, besides adhering tissue and meat, also a considerable content of high-quality nutritive substances. An apparatus for retrieving them, disclosed in Austrian patent 374,092, places the bones in water containing receptacle, stirs and, optionally, strikes the contents and then subjects the contents to a sieving process for collection of the liquid and fine constituents beneath the sieve. The residual mass containing the bones is fed from the sieve into a press cylinder and is pressed for obtaining the residual liquid. A high portion of the nutritive substances in or on the bones can thereby be obtained; however, the separation of the liquid constituents from the residual constituents is too coarse. Namely, if the sieve is made too fine, too much of the nutritive substances get into the press chamber, where they can only be partially recovered. If, however, the sieve has comparatively large penetration openings, fine bone parts or fibers may pass, which in most cases is undesirable.
From German published patent application DE-OS 2,157,850 it is known to obtain useful substances from bones and meat adhering thereon by comminuting the cooled starting material and to mix it with water or ice, whereupon the suspension obtained is centrifuged into a solid phase and a liquid phase. This procedure requires great effort in apparatus and has the disadvantage that a considerable heating up occurs during centrifuging which must be compensated by supplying additional cooling.